The present invention relates to a sheet feed system for a facsimile transmission system, electrostatic copying machine or the like.
In electrostatic copying machines a cassette system has been introduced to facilitate the use of copy sheets of different sizes. In such a system, different sized copy sheets are provided in respective cassettes which are selectively inserted into the copying machine as desired. This cassette system provides faster changing of paper sizes than in the conventional system in which stacks of paper must be changed, guides adjusted, etc.
In order to further increase the speed of changing paper sizes, copying machines have been proposed in which two cassettes may be inserted in the copying machine and the desired cassette selected by means of a lever or switch. Although such a system provides a speed-up in copy sheet changeover, two feed systems for the respective cassettes are provided which increases the cost and complexity of the machine.
In an attempt to simplify such a system, a combination cassette has been proposed in which a single feed system is utilized for two copy sheet cassettes. In addition to the complex construction of this prior art combination cassette, a disadvantage is found in that it is difficult to load a fresh supply of copy sheets into the lower cassette.
Similar problems are found in facsimile transceivers which are used to reproduce documents by means of electrical signals transmitted over telephone lines or by wireless. Generally, a drum is provided on which an original document is wrapped for scanning and on which a copy sheet is wrapped for reproduction of a transmitted document. Recently, automatic feed mechanisms have been introduced to automatically feed either documents or copy sheets onto the drum. This enables automatic continuous transmission and reception and also unattended reception. Most of these systems have separate feed mechanisms for the documents and copy sheets, which increases the cost of the systems.
In such facsimile systems, mode switches are generally provided on the control consoles to switch between single document transmission, multiple document transmission and reception modes. An end switch is also provided which must be depressed at the termination of multiple document transmission. These switches increase the complexity of operation and thereby invite erroneous operation by persons such as office workers who have no understanding of electronic systems. It is also possible for a skilled person to accidently actuate the wrong switch and cause erroneous operation. It is particularly desirable to avoid mistakes in operation in the case of overseas facsimile transmission over telephone lines due to the high telephone charges.